Motion evaluation system and method

ABSTRACT

A motion evaluation system includes a marker member including a body part having a first surface and a second surface parallel to the first surface, a reference indication part indicating a center of the first surface, and a plurality of markers arranged on the first surface to be spaced apart from the reference indication part. The marker member is arranged on an object such that the reference indication part is arranged at a reference point of a first coordinate system. A plurality of cameras generate coordinate images by respectively photographing the markers. A first coordinate calculator calculates first coordinate values of the markers in a first coordinate system by using separation distances of the markers and a first distance between the first surface and the second surface, the separation distances and the first distance being previously stored. A second coordinate calculator calculates second coordinate values of the markers in a second coordinate system by using the coordinate images generated by the cameras. A coordinate converter produces a conversion relationship between the first coordinate system and the second coordinate system by using the first coordinate values and the second coordinate values of the markers, and converts second motion information in the second coordinate system corresponding to a motion of the object objected by using the cameras to first motion information in the first coordinate system.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2016-0049406, filed on Apr. 22, 2016, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND 1. Field

One or more embodiments relate to a motion evaluation system and method.

2. Description of the Related Art

In recent years, with the development of medical devices and advances inmedical technology, medical devices have become more advanced. Forexample, in the treatment of cancer, surgical treatment, medication,and/or radiation treatment have been the mainstream. However, recently,a particle beam treatment apparatus has been developed, whereby particlebeams such as proton beams or carbon beams are irradiated to a subjectfor treatment thereof. The treatment with the particle beam treatmentapparatus is characteristically non-invasive and allows a patient torecover quickly after being treated.

In the treatment by using the particle beam treatment apparatus, thetreatment is performed based on the Bragg peak, which is acharacteristic of the particles. When a couch on which a patient is laidis not located at an accurate position during treatment, an unexpectedamount of radiation may be irradiated onto an organ of the patient andthus the organ may be damaged if the patient has high radiationsensitivity. Accordingly, the position of the couch used for theparticle beam treatment needs to be precisely controlled.

In the related art, to evaluate the motion of a couch, graphic paper,laser, or a goniometer has been used. However, since the above methodsdepend on the visual determination of a person, these methods may giveerroneous results and thus it may be practically difficult to evaluatethe precise motion of a couch.

SUMMARY

One or more embodiments include a motion evaluation system and method,whereby the motion of an object such as a couch can be preciselyevaluated by using a marker member.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to one or more embodiments, a motion evaluation systemincludes a marker member including a body part having a first surfaceand a second surface parallel to the first surface, a referenceindication part indicating a center of the first surface, and aplurality of markers arranged on the first surface to be spaced apartfrom the reference indication part, wherein the marker member isarranged on an object such that the reference indication part isarranged at a reference point of a first coordinate system, a pluralityof cameras configured to generate coordinate images by respectivelyphotographing the plurality of markers, a first coordinate calculatorconfigured to calculate first coordinate values of the plurality ofmarkers in a first coordinate system by using separation distances ofthe plurality of markers and a first distance between the first surfaceand the second surface, the separation distances and the first distancebeing previously stored, a second coordinate calculator configured tocalculate second coordinate values of the plurality of markers in asecond coordinate system by using the coordinate images generated by theplurality of cameras, and a coordinate converter configured to produce aconversion relationship between the first coordinate system and thesecond coordinate system by using the first coordinate values and thesecond coordinate values of the plurality of markers, and to convertsecond motion information in the second coordinate system correspondingto a motion of the object objected by using the plurality of cameras tofirst motion information in the first coordinate system.

The motion evaluation system may further include a laser memberindicating a reference point of the first coordinate system.

The marker member may include at least three markers.

The markers may include a first marker, a second marker, a third marker,and a fourth marker arranged on the first surface of the body part.

The first coordinate calculator may calculate a three-dimensional (3D)first coordinate value of the plurality of markers by using the firstmarker, the second marker, the third marker, and the fourth marker.

The first coordinate calculator may calculate a first-1 coordinatevalue, a first-2 coordinate value, a first-3 coordinate value, and afirst-4 coordinate value respectively corresponding to the first marker,the second marker, the third marker, and the fourth marker and a first-5coordinate value, a first-6 coordinate value, a first-7 coordinatevalue, and a first-8 coordinate value at positions respectivelycorresponding to the first marker, the second marker, the third marker,and the fourth marker on the second surface.

The second coordinate calculator may calculate a 3D second coordinatevalue of the plurality of markers by using the first marker to thefourth marker.

The second coordinate calculator may calculate a second-1 coordinatevalue, a second-2 coordinate value, a second-3 coordinate value, and asecond-4 coordinate value of the first marker, the second marker, thethird marker, and the fourth marker corresponding to the secondcoordinate system by using the coordinate images generated by theplurality of cameras, and calculate a second-5 coordinate value, asecond-6 coordinate value, a second-6 coordinate value, and a second-8coordinate value on the second surface at positions respectivelycorresponding to the first marker, the second marker, the third marker,and the fourth marker by using the previously stored separationdistances of the plurality of markers and first distance, and thecalculated second-1 coordinate value, the calculated second-2 coordinatevalue, the calculated second-3 coordinate value, and the calculatedsecond-4 coordinate value.

The coordinate converter may produce a conversion matrix that defines aconversion relationship between the first coordinate system and thesecond coordinate system by generating a first matrix of the first-1coordinate value, the first-2 coordinate value, the first-3 coordinatevalue, the first-4 coordinate value, the first-5 coordinate value, thefirst-6 coordinate value, the first-7 coordinate value, and the first-8coordinate value, generating a second matrix of the second-1 coordinatevalue, the second-2 coordinate value, the second-3 coordinate value, thesecond-4 coordinate value, the second-5 coordinate value, the second-6coordinate value, the second-7 coordinate value, and the second-8coordinate value, calculating an inverse matrix of any one of the firstmatrix and the second matrix, and calculating the inverse matrix and theother one of the first matrix and the second matrix.

According to one or more embodiments, a motion evaluation methodincludes preparing a marker member on an object, the marker membercomprising a body part having a first surface and a second surfaceparallel to the first surface, a reference indication part indicating acenter of the first surface, and a plurality of markers arranged on thefirst surface to be spaced apart from the reference indication part,arranging a center of the first surface of the marker member at areference point of a first coordinate system, calculating, by using afirst coordinate calculator, first coordinate values of the plurality ofmarkers in a first coordinate system by using separation distances ofthe plurality of markers and a first distance between the first surfaceand the second surface, the separation distances and the first distancebeing previously stored, generating, by using a plurality of cameras,coordinate images of a plurality of markers by photographing theplurality of markers, calculating, by using a second coordinatecalculator, second coordinate values of the plurality of markers in asecond coordinate system by using the coordinate images generated by theplurality of cameras, and producing a conversion relationship betweenthe first coordinate system and the second coordinate system by usingthe first coordinate values and the second coordinate values of theplurality of markers.

The motion evaluation method may further include converting, by usingthe coordinate converter, second motion information in the secondcoordinate system corresponding to a motion of the object objected byusing the plurality of cameras, to first motion information in the firstcoordinate system.

The motion evaluation method may further include indicating a referencepoint of the first coordinate system by using a laser member.

The marker member may include at least three markers.

The plurality of markers may include a first marker, a second marker, athird marker, and a fourth marker arranged on the first surface of thebody part.

The calculating of the first coordinate value may include calculating athree-dimensional (3D) first coordinate value of the plurality ofmarkers by using the first marker, the second marker, the third marker,and the fourth marker.

The calculating of the first coordinate value may include calculating afirst-1 coordinate value to a first-4 coordinate value corresponding tothe first marker, the second marker, the third marker, and the fourthmarker, and calculating a first-5 coordinate value to a first-8coordinate value at positions corresponding to the first marker, thesecond marker, the third marker, and the fourth marker on the secondsurface of the body part.

The calculating of the second coordinate valve may include calculating a3D second coordinate value of the plurality of markers by using thefirst marker, the second marker, the third marker, and the fourthmarker.

The calculating of the second coordinate value may include calculating asecond-1 coordinate value to a second-4 coordinate value of the firstmarker to the fourth marker corresponding to the second coordinatesystem by using the coordinate images, and calculating a second-5coordinate value to a second-8 coordinate value on the second surface ofthe body part at positions corresponding to the first marker to thefourth marker by using the previously stored separation distances of theplurality of markers and first distance, and the calculated second-1coordinate value to second-4 coordinate value.

The producing of the conversion relationship may include generating afirst matrix of the first-1 coordinate value to the first-8 coordinatevalue, generating a second matrix of the second-1 coordinate value tothe second-8 coordinate value, calculating an inverse matrix of any oneof the first matrix and the second matrix, and calculating the inversematrix and the other one of the first matrix and the second matrix,thereby producing a conversion matrix defining a conversion relationshipbetween the first coordinate system and the second coordinate system.

According to one or more embodiments, a non-transitory computer readablerecording medium having recorded thereon a program, which when executedby a computer, performs the motion evaluation method, which includespreparing a marker member on an object, the marker member comprising abody part having a first surface and a second surface parallel to thefirst surface, a reference indication part indicating a center of thefirst surface, and a plurality of markers arranged on the first surfaceto be spaced apart from the reference indication part, arranging acenter of the first surface of the marker member at a reference point ofa first coordinate system, calculating, by using a first coordinatecalculator, first coordinate values of the plurality of markers in afirst coordinate system by using separation distances of the pluralityof markers and a first distance between the first surface and the secondsurface, the separation distances and the first distance beingpreviously stored, generating, by using a plurality of cameras,coordinate images of a plurality of markers by photographing theplurality of markers, calculating, by using a second coordinatecalculator, second coordinate values of the plurality of markers in asecond coordinate system by using the coordinate images generated by theplurality of cameras, and producing a conversion relationship betweenthe first coordinate system and the second coordinate system by usingthe first coordinate values and the second coordinate values of theplurality of markers.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic block diagram of a motion evaluation systemaccording to an embodiment;

FIG. 2 schematically illustrates the motion evaluation system of FIG. 1according to an embodiment;

FIGS. 3 and 4 are perspective views schematically illustrating therelationship among a plurality of markers of the marker member of FIG. 2according to an embodiment; and

FIG. 5 is a flowchart for sequentially explaining a motion evaluationmethod according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list.

As the inventive concept allows for various changes and numerousembodiments, embodiments will be illustrated in the drawings anddescribed in detail in the written description. However, this is notintended to limit the present inventive concept to particular modes ofpractice, and it is to be appreciated that all changes, equivalents, andsubstitutes that do not depart from the spirit and technical scope ofthe present inventive concept are encompassed in the present inventiveconcept. In the description of the present inventive concept, certaindetailed explanations of the related art are omitted when it is deemedthat they may unnecessarily obscure the essence of the inventiveconcept.

It will be understood that although the terms “first,” “second,” etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another.

As used herein, the singular forms “a,” “an” and the are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

It will be understood that when a layer, region, or component isreferred to as being “formed on” another layer, region, or component, itcan be directly or indirectly formed on the other layer, region, orcomponent. That is, for example, intervening layers, regions, orcomponents may be present.

Sizes of components in the drawings may be exaggerated for convenienceof explanation. In other words, since sizes and thicknesses ofcomponents in the drawings are arbitrarily illustrated for convenienceof explanation, the following embodiments are not limited thereto.

When a certain embodiment may be implemented differently, a specificprocess order may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order.

In the present specification, when a layer, region, or component“connects” or is “connected” to another layer, region, or component, thelayer, region, or component may contact or may be connected to the otherlayer, region, or component not only directly, but also electricallythrough at least one of other layer, region, or components interposedtherebetween.

FIG. 1 is a schematic block diagram of a motion evaluation system 10according to an embodiment. FIG. 2 schematically illustrates the motionevaluation system 10 of FIG. 1 according to an embodiment.

Referring to FIGS. 1 and 2, the motion evaluation system 10 according tothe present embodiment may include a laser member 110, a marker member120, a plurality of cameras 130, a first coordinate calculator 140, asecond coordinate calculator 150, and a coordinate converter 160.

The laser member 110 may indicate a reference point C0 of a firstcoordinate system by using a laser beam. The first coordinate system isa coordinate system of an object R. The object R may be a couch that canmove. The coordinate system of the object R is the same as athree-dimensional (3D) coordinate system of a treatment room where theobject R may be placed. The laser member 110, as illustrated in thedrawings, may indicate the reference point C0 of the first coordinatesystem by irradiating a laser beam in a cross (+) shape.

The marker member 120 may be arranged on the object R that is movable.The marker member 120 may include a body part 123 having a first surface123-1 (see FIG. 3) and a second surface 123-2 (see FIG. 3) parallel tothe first surface 123-1, a reference indication part 125 indicating acenter of the first surface 123-1, and a plurality of markers 121arranged on the first surface 123-1 and spaced apart from the referenceindication part 125. The markers 121 are infrared (IR) markers and maybe of either a passive type or an active type. A passive type marker isformed of a material that reflects an IR ray irradiated from theoutside. In this state, the cameras 130 may detect reflected light andgenerate a coordinate image. An active type marker may directly emitlight such as an IR ray, and the cameras 130 may detect the light andgenerate a coordinate image. The present inventive concept is notlimited regarding the marker type. However, in the followingdescription, a passive type marker is described as an example forconvenience of explanation.

The marker member 120 may include at least three markers 121 to obtain a3D coordinate value. However, four or more markers may be included toincrease the accuracy of evaluating a motion. In the present embodiment,use of four markers is described as an example.

FIGS. 3 and 4 are perspective views schematically illustrating therelation between the markers 121 of the marker member 120 of FIG. 2.

Referring to FIG. 3, the marker member 120 may include the body part123. The body part 123 may include the first surface 123-1 and thesecond surface 123-2 parallel to the first surface 123-1. For example,the body part 123 may be a cube or a cuboid having six faces, theadjacent faces meeting at 90 degrees with one another. Furthermore,lengths w1, w2, and w3 of the respective edges of the body part 123 arealready known information, and the body part 123 may be formed of amaterial such that the lengths w1, w2, and w3 of the respective edgesare not changed by external factors. In detail, a first distance w3,which is a distance between the first surface 123-1 and the secondsurface 123-2, may indicate a height from the object R to the markers121.

The markers 121 may include a first marker 121A, a second marker 121B, athird marker 121C, and a fourth marker 121D, which are arranged on thefirst surface 123-1 of the body part 123. For example, the first marker121A to the fourth marker 121D may be arranged adjacent to therespective corners of the first surface 123-1 of the body part 123. Thedistances between the markers 121, that is, a first separation distanced1 between the first marker 121A and the second marker 121B and a secondseparation distance d2 between the second marker 121B and the fourthmarker 121D, are also already known information.

The marker member 120 may include the reference indication part 125indicating the center of the first surface 123-1 of the body part 123.The reference indication part 125 may have a cross (+) shape and may beformed at an intersection of lines perpendicularly passing throughcenter points of the respective edges.

Referring to FIGS. 1 to 4, the first coordinate calculator 140 maypreviously store the separation distances d1 and d2 between the markers121 and the lengths w1, w2, and w3 of the respective edges of the bodypart 123, in detail, the first distance w3 between the first surface123-1 and the second surface 123-2. The first coordinate calculator 140may calculate first coordinate values of the markers 121 in the firstcoordinate system by using the previously stored separation distances d1and d2 between the markers 121 and first distance w3. The firstcoordinate values may be a 3D first coordinate value of the markers 121.

In detail, the first coordinate calculator 140 may calculate a first-1coordinate value A1, a first-2 coordinate value A2, a first-3 coordinatevalue A3, and a first-4 coordinate value A4 respectively correspondingto the first marker 121A, the second marker 121B, the third marker 121C,and the fourth marker 121D with respect to the reference point C0 of thefirst coordinate system. Furthermore, the first coordinate calculator140 may calculate a first-5 coordinate value A5, a first-6 coordinatevalue A6, a first-7 coordinate value A7, and a first-8 coordinate valueA8 on the second surface 123-2 at positions respectively correspondingto the first marker 121A, the second marker 121B, the third marker 121C,and the fourth marker 121D. In other words, the first coordinatecalculator 140 may calculate eight (8) coordinate values in the firstcoordinate system by using the information of the marker member 120.

Referring back to FIGS. 1 and 2, the cameras 130 may generate coordinateimages by photographing the markers 121 of the marker member 120. Thecameras 130 may generate coordinate images of the markers 121 byphotographing IR rays reflected from the markers 121 and returned to thecameras 130. Although not illustrated, an IR ray is irradiated by usingan IR generator (not shown) and the irradiated IR ray is reflected fromeach of the markers 121. In an embodiment, a plurality of IR generatorsare installed in various directions to irradiate IR rays, and a circleis searched for by using a circle fitting method using the brightestpixels from the coordinate images photographed and generated by themarkers 121, thereby identifying the positions of the markers 121 byobtaining a center coordinate of a found circle. However, the presentdisclosure is not limited thereto. In another embodiment, when the IRgenerators are arranged in various directions to irradiate IR rays, thecenter of the markers 121 shines the brightest. The cameras 130 find theposition of the brightest pixel and thus the positions of the markers121 may be identified. The second coordinate calculator 150 describedlater may calculate second coordinate values of the markers 121 in asecond coordinate system through the above coordinate images. The numberof cameras theoretically required to obtain a 3D second coordinate valueis two. However, just an approximate 3D position may be identified byusing only two cameras. Accordingly, at least three cameras are neededto identify an accurate 3D position. In FIG. 2, four cameras areillustrated as the cameras 130 for improvement the accuracy ofidentifying the 3D position.

The second coordinate calculator 150 may calculate second coordinatevalues in the second coordinate system of the markers 121 based on thecoordinate images generated by the cameras 130. The second coordinatecalculator may calculate a 3D second coordinate value of the markers 121by using the first marker 121A, the second marker 121B, the third marker121C, and the fourth marker 121D.

The second coordinate calculator 150 may calculate a second-1 coordinatevalue, a second-2 coordinate value, a second-3 coordinate value, and asecond-4 coordinate value in the second coordinate system of the firstmarker 121A, the second marker 121B, the third marker 121C, and thefourth marker 121D by using the coordinate images generated by thecameras 130. The second coordinate calculator 150, like the firstcoordinate calculator 140, may previously store the separation distancesd1 and d2 of the markers 121 and the lengths w1, w2, and w3 of therespective edges of the body part 123 including at least the firstdistance w3 between the first surface 123-1 and the second surface123-2. Accordingly, the second coordinate calculator 150 may calculate asecond-5 coordinate value, a second-6 coordinate value, a second-7coordinate value, and a second-8 coordinate value on the second surface123-2 at positions corresponding to the first marker 121A, the secondmarker 121B, the third marker 121C, and the fourth marker 121D. In otherwords, the second coordinate calculator 150 may calculate eight (8)second coordinate values in the second coordinate system.

The coordinate converter 160 may produce a conversion relationshipbetween the first coordinate system and the second coordinate system byusing the first coordinate values and the second coordinate values ofthe markers 121. The coordinate converter 160 may convert second motioninformation in the second coordinate system corresponding to a motion ofthe object R obtained by using the cameras 130 to first motioninformation in the first coordinate system.

According to an embodiment, the motion evaluation system 10 having theabove structure may enable accurate location tracking of the object R byusing the marker member 120 and the cameras 130. As the location isconverted to the first coordinate system corresponding to a treatmentroom coordinate system, the motion of the object R may be accuratelyevaluated.

The method of evaluating a motion according to an embodiment isdescribed in detail with reference to FIGS. 1 to 5.

FIG. 5 is a flowchart for sequentially explaining a motion evaluationmethod according to an embodiment.

Referring to FIG. 5, according to the motion evaluation method accordingto the present embodiment, first, the marker member 120 including thebody part 123 having the first surface 123-1 and the second surface123-2 parallel to the first surface 123-1, the reference indication part125 indicating the center of the first surface, and the markers 121arranged on the first surface 123-1 and spaced apart from the referenceindication part 125 is prepared on the object R.

Then, the center of the first surface 123-1 of the marker member 120 isarranged at the reference point C0 of the first coordinate system (S11).The reference point C0 of the first coordinate system is indicated bythe laser member 110. Furthermore, since the marker member 120 includesthe reference indication part 125 that indicates the center of the firstsurface 123-1 of the body part 123, the position of the marker member120 may be determined by aligning the reference indication part 125 ofthe marker member 120 and the reference point C0 of the first coordinatesystem.

Next, the first coordinate values of the markers 121 in the firstcoordinate system are calculated by using the first coordinatecalculator 140 (S21). The separation distances d1 and d2 of the markers121 and the lengths w1 w2, and w3 of the respective edges of the bodypart 123 including at least the first distance w3 between the firstsurface 123-1 and the second surface 123-2 may be previously stored inthe first coordinate calculator 140. A 3D first coordinate value of themarkers 121 may be calculated by the first coordinate calculator 140 byusing the separation distances d1 and d2 of the markers 121 and thefirst distance w3. For example, a first coordinate value of a referencepoint may be (0, 0, 0), a first-1 coordinate value of the first marker121A may be (−d1/2, −d2/2, 0), and a first-5 coordinate value may be(−d1/2, −d2/2, −w3). Likewise, the other first coordinate values arecalculated in the same manner, and thus a total eight (8) firstcoordinate values may be calculated.

Next, coordinate images are generated by photographing the markers 121by using the cameras 130 (S22). A process of forming a virtual 3Dcoordinate is needed before the photographing of the markers 121 byusing the cameras 130, which is referred to as calibration.

Calibration is needed for the following reasons. A 3D second coordinatesystem may be set to be within a range where the cameras 130 may captureimages. The position (0, 0, 0) may be set by a user and to match thereference point C0 of the first coordinate system. A relationshipbetween the 3D second coordinate system and the coordinated of each ofthe cameras 130 is obtained by calculating the distance and direction ofeach of the cameras 130 for photographing, and a distorted coordinate ofa camera lens may be corrected. The lenses of the cameras 130 used bythe motion evaluation method may include various lenses from awide-angle lens (8 mm) to standard zoom lens, a single lens, and atelephoto lens. In the case of a wide-angle lens, since a distortionphenomenon occurs further from the center toward the periphery in acamera screen, the distortion phenomenon needs to be corrected by usinga software algorithm. Since every lens is affected by the distortionphenomenon, an algorithm may be used to identify a degree of distortionof each lens and correct the distortion through calibration prior tomeasurement.

The calibration may be performed via various methods. For example, aT-shaped wand with already known specifications is previously measuredand then coordinate calculation variables are corrected to match imageinformation acquired by the cameras 130 with the specifications of theT-shaped wand. First, for dynamic calibration, the T-shaped wand may bemoved so as to be properly photographed by all of the cameras 130. Afterthe motion measurement, the T-shaped wand is placed at a position wherethe coordinate (0, 0, 0) is desired to be generated, thereby performingstatic calibration.

After the calibration process, coordinate images of the markers 121 maybe generated by using the cameras 130.

Next, the second coordinate values of the markers 121 in the secondcoordinate system are calculated by the second coordinate calculator 150by using the coordinate images (S23). First, the second coordinatecalculator 150 may calculate the second-1 coordinate value, the second-2coordinate value, the second-3 coordinate value, and the second-4coordinate value in the second coordinate system of the first marker121A, the second marker 121B, the third marker 121C, and the fourthmarker 121D, by using the coordinate images. The second coordinatecalculator 150 previously store the separation distances d1 and d2 ofthe markers 121 and the first distance w3, and the second-5 coordinatevalue, the second-6 coordinate value, the second-7 coordinate value, andthe second-8 coordinate value on the second surface 123-2 at positionscorresponding to the first marker 121A, the second marker 121B, thethird marker 1210, and the fourth marker 121D may be calculated usingthe stored data (S23).

Next, a conversion relationship between the first coordinate system andthe second coordinate system may be produced by the coordinate converter160 by using the first coordinate values and the second coordinatevalues of the markers 121. In detail, the coordinate converter 160generates a first matrix of the first-1 coordinate value A1, the first-2coordinate value A2, the first-3 coordinate value A3, the first-4coordinate value A4, the first-5 coordinate value A5, the first-6coordinate value A6, the first-7 coordinate value A7, and the first-8coordinate value A8. A first matrix R that represents the firstcoordinate system, that is, a treatment room coordinate system, may beexpressed as [X, Y, Z, 1]T. Furthermore, the coordinate converter 160generates a second matrix of the second-1 coordinate value, the second-2coordinate value, the second-3 coordinate value, the second-4 coordinatevalue, the second-5 coordinate value, the second-6 coordinate value, thesecond-7 coordinate value, and the second-8 coordinate value. A secondmatrix V that represents the second coordinate system, that is, a cameracoordinate system, may be expressed by [X, Y, Z, 1]T. Since each of thefirst matrix and the second matrix includes eight (8) coordinate values,each of the first matrix and the second matrix may be expressed byEquation 1. Furthermore, a correlationship between the first matrix andthe second matrix may be defined by Equation 2.V=[V ₁ V ₂ V ₃ V ₄ V ₅ V ₆ V ₇ V ₈]R=[R ₁ R ₂ R ₃ R ₄ R ₅ R ₆ R ₇ R ₈]  [Equation 1]R=TV  [Equation 2]

A conversion relationship may be produced by using the abovecorrelationship. In other words, the coordinate converter 160 calculatesan inverse matrix of any one of the first matrix and the second matrixand then calculates the inverse matrix and the other one of the firstmatrix and the second matrix, thereby producing a conversion matrix asexpressed by Equation 3 (S31).T=RV ⁻¹  [Equation 3]

The size of each of the first matrix and the second matrix may be 4×8,and the size of a conversion matrix TVR may be 4×4.

Then, the second motion information in the second coordinate systemcorresponding to a motion of the object R obtained by using the cameras130 may be converted to the first motion information in the firstcoordinate system by using the conversion relationship produced by thecoordinate converter 160 (S41). In this regard, according to the motionevaluation method including the above-described operations, the motionof the object R may be accurately tracked and converted to the firstcoordinate system, that is, the treatment room coordinate system, andthen provided for use. Thus, the motion of the object R in the firstcoordinate system may be accurately evaluated.

Examples of a non-transitory computer-readable recording medium storingcomputer commands to execute the motion evaluation method includemagnetic media, e.g., hard disks, floppy disks, and magnetic tapes,optical media, e.g., compact disc read only memories (CD-ROMs) anddigital versatile disks (DVDs), magneto-optical media, e.g., flopticaldisks, and hardware device configured to store and execute programcommands, for example, programming modules, e.g., read only memories(ROMs), random access memories (RAMs), flash memories. Also, the programcommands may include not only machine codes created by a compiler butalso high-level language codes executable by a computer using aninterpreter. The above-described hardware apparatuses may be configuredto operate as one or more software modules to perform operationsaccording to various embodiments of the present inventive concept, orvise versa.

The computer program may be specially designed and configured for thepresent inventive concept or may be well-known to one skilled in the artof computer software, to be usable. An example of a computer program mayinclude not only machine codes created by a compiler but also high-levellanguage codes executable by a computer using an interpreter.

The particular implementations shown and described herein areillustrative examples of the inventive concept and are not intended tootherwise limit the scope of the inventive concept in any way. For thesake of brevity, conventional electronics, control systems, softwaredevelopment and other functional aspects of the systems may not bedescribed in detail. Furthermore, the connecting lines, or connectorsshown in the various figures presented are intended to representfunctional relationships and/or physical or logical couplings betweenthe various elements. It should be noted that many alternative oradditional functional relationships, physical connections or logicalconnections may be present in a practical device. Moreover, no item orcomponent is essential to the practice of the inventive concept unlessthe element is specifically described as “essential” or “critical.”

As described above, according to the motion evaluation system accordingto the above-described embodiment, an accurate position of an object maybe tracked by using the marker member and the cameras, and by convertingthe position to the first coordinate system corresponding to a treatmentroom coordinate system, a motion of the object may be accuratelyevaluated.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. A motion evaluation system comprising: a markermember comprising a body part having a first surface and a secondsurface parallel to the first surface, a reference indication partindicating, a center of the first surface, and a plurality of markersarranged on the first surface to be spaced apart from the referenceindication part, wherein the marker member is arranged on an object suchthat the reference indication part is arranged at a reference point of afirst coordinate system; a plurality of cameras configured to generatecoordinate images by respectively photographing the plurality ofmarkers; a first coordinate calculator configured to calculate firstcoordinate values of the plurality of markers in a first coordinatesystem by using separation distances of the plurality of markers and afirst distance between the first surface and the second surface, theseparation distances and the first distance being previously stored; asecond coordinate calculator configured to calculate second coordinatevalues of the plurality of markers in a second coordinate system byusing the coordinate images generated by the plurality of cameras; and acoordinate converter configured to produce a conversion relationshipbetween the first coordinate system and the second coordinate system byusing the first coordinate values and the second coordinate values ofthe plurality of markers, and to convert second motion information inthe second coordinate system corresponding to a motion of the objectobjected by using the plurality of cameras to first motion informationin the first coordinate system.
 2. The motion evaluation system of claim1, further comprising a laser member indicating a reference point of thefirst coordinate system.
 3. The motion evaluation system of claim 1,wherein the marker member comprises at least three markers.
 4. Themotion evaluation system of claim 3, wherein the plurality of markerscomprise a first marker, a second marker, a third marker, and a fourthmarker arranged on the first surface of the body part.
 5. The motionevaluation system of claim 4, wherein the first coordinate calculatorcalculates a three-dimensional (3D) first coordinate value of theplurality of markers by using the first marker, the second marker, thethird marker, and the fourth marker.
 6. The motion evaluation system ofclaim 5, wherein the first coordinate calculator calculates a first-1coordinate value, a first-2 coordinate value, a first-3 coordinatevalue, and a first-4 coordinate value respectively corresponding to thefirst marker, the second marker, the third marker, and the fourth markerand a first-5 coordinate value, a first-6 coordinate value, a first-7coordinate value, and a first-8 coordinate value at positionsrespectively corresponding to the first marker, the second marker, thethird marker, and the fourth marker on the second surface.
 7. The motionevaluation system of claim 6, wherein the second coordinate calculatorcalculates a 3D second coordinate value of the plurality of markers byusing the first marker to the fourth marker.
 8. The motion evaluationsystem of claim 7, wherein the second coordinate calculator calculates asecond-1 coordinate value, a second-2 coordinate value, a second-3coordinate value, and a second-4 coordinate value of the first marker,the second marker, the third marker, and the fourth marker correspondingto the second coordinate system by using the coordinate images generatedby the plurality of cameras, and calculates a second-5 coordinate value,a second-6 coordinate value, a second-6 coordinate value, and a second-8coordinate value on the second surface at positions respectivelycorresponding to the first marker, the second marker, the third marker,and the fourth marker by using the previously stored separationdistances of the plurality of markers and first distance, and thecalculated second-1 coordinate value, the calculated second-2 coordinatevalue, the calculated second-3 coordinate value, and the calculatedsecond-4 coordinate value.
 9. The motion evaluation system of claim 8,wherein the coordinate converter produces a conversion matrix thatdefines a conversion relationship between the first coordinate systemand the second coordinate system by generating a first matrix of thefirst-1 coordinate value, the first-2 coordinate value, the first-3coordinate value, the first-4 coordinate value, the first-5 coordinatevalue, the first-6 coordinate value, the first-7 coordinate value, andthe first-8 coordinate value, generating a second matrix of the second-1coordinate value, the second-2 coordinate value, the second-3 coordinatevalue, the second-4 coordinate value, the second-5 coordinate value, thesecond-6 coordinate value, the second-7 coordinate value, and thesecond-8 coordinate value, calculating an inverse matrix of any one ofthe first matrix and the second matrix, and calculating the inversematrix and the other one of the first matrix and the second matrix. 10.A motion evaluation method comprising: preparing a marker member on anobject, the marker member comprising a body part having a first surfaceand a second surface parallel to the first surface, a referenceindication part indicating a center of the first surface, and aplurality of markers arranged on the first surface to be spaced apartfrom the reference indication part; arranging a center of the firstsurface of the marker member at a reference point of a first coordinatesystem; calculating, by using a first coordinate calculator, firstcoordinate values of the plurality of markers in a first coordinatesystem by using separation distances of the plurality of markers and afirst distance between the first surface and the second surface, theseparation distances and the first distance being previously stored;generating, by using a plurality of cameras, coordinate images of aplurality of markers by photographing the plurality of markers;calculating, by using a second coordinate calculator, second coordinatevalues of the plurality of markers in a second coordinate system byusing the coordinate images generated by the plurality of cameras; andproducing a conversion relationship between the first coordinate systemand the second coordinate system by using the first coordinate valuesand the second coordinate values of the plurality of markers.
 11. Themotion evaluation method of claim 10, further comprising: converting, byusing the coordinate converter, second motion information in the secondcoordinate system corresponding to a motion of the object objected byusing the plurality of cameras, to first motion information in the firstcoordinate system.
 12. The motion evaluation method of claim 10, furthercomprising: indicating a reference point of the first coordinate systemby using a laser member.
 13. The motion evaluation method of claim 10,wherein the marker member comprises at least three markers.
 14. Themotion evaluation method of claim 13, wherein the plurality of markerscomprise a first marker, a second marker, a third marker, and a fourthmarker arranged on the first surface of the body part.
 15. The motionevaluation method of claim 14, wherein the calculating of the firstcoordinate value comprises calculating a three-dimensional (3D) firstcoordinate value of the plurality of markers by using the first marker,the second marker, the third marker, and the fourth marker.
 16. Themotion evaluation method of claim 15, wherein the calculating of thefirst coordinate value comprises: calculating a first-1 coordinate valueto a first-4 coordinate value corresponding to the first marker, thesecond marker, the third marker, and the fourth marker; and calculatinga first-5 coordinate value to a first-8 coordinate value at positionscorresponding to the first marker, the second marker, the third marker,and the fourth marker on the second surface of the body part.
 17. Themotion evaluation method of claim 16, wherein the calculating of thesecond coordinate valve comprises calculating a 3D second coordinatevalue of the plurality of markers by using the first marker, the secondmarker, the third marker, and the fourth marker.
 18. The motionevaluation method of claim 17, wherein the calculating of the secondcoordinate value comprises: calculating a second-1 coordinate value to asecond-4 coordinate value of the first marker to the fourth markercorresponding to the second coordinate system by using the coordinateimages; and calculating a second-5 coordinate value to a second-8coordinate value on the second surface of the body part at positionscorresponding to the first marker to the fourth marker by using thepreviously stored separation distances of the plurality of markers andfirst distance, and the calculated second-1 coordinate value to second-4coordinate value.
 19. The motion evaluation method of claim 18, whereinthe producing of the conversion relationship comprises; generating afirst matrix of the first-1 coordinate value to the first-8 coordinatevalue; generating a second matrix of the second-1 coordinate value tothe second-8 coordinate value; calculating an inverse matrix of any oneof the first matrix and the second matrix; and calculating the inversematrix and the other one of the first matrix and the second matrix,thereby producing a conversion matrix defining a conversion relationshipbetween the first coordinate system and the second coordinate system.20. A non-transitory computer readable recording medium having recordedthereon a program, which when executed by a computer, performs themethod of claim 10.